沙丁胺醇对大鼠树突状细胞功能的调节

Salbutamol down regulate bone marrow-derived dendritic cells function but may not via adrenergic receptor

目的:探讨β2受体激动剂沙丁胺醇调节树突状细胞(dendritic cells,DCs)免疫功能的机制。方法:采用重组大鼠粒-单集落刺激因子(recombinant rat granulocyte monocytes colony-stimulating factor,rrGM-CSF)和重组大鼠白细胞介素4(recombinant rat interleukin-4,rrIL-4)从SD大鼠骨髓细胞诱导获得幼稚DCs,然后采用LPS诱导成熟。在DCs中分别和联合加入β2受体激动剂沙丁胺醇及其阻断剂丁氧胺,应用光镜和共聚焦显微镜观察沙丁胺醇对DCs形态学改变的影响,采用流式细胞术分析DCs表面标志的变化,最终用混合淋巴细胞反应检测DCs功能的变化。结果:倒置显微镜下,细胞形态学观察未发现实验组与对照组之间有明显差别;流式细胞术分析表明:沙丁胺醇上调大鼠DCs相对特异性标志OX62的表达,下调共刺激分子CD80,CD86和MHC-Ⅱ类分子,但对髓系标志CD11c无明显影响;丁氧胺可下调CD11c,MHC-Ⅱ,CD80和CD86的表达,但对OX62的表达无明显影响;沙丁胺醇与丁氧胺联合应用可明显下调CD80和CD86,MHC-Ⅱ,CD11c的表达,上调OX62的表达;混合淋巴细胞反应结果显示沙丁胺醇可以抑制DCs刺激T细胞增殖的能力;丁氧胺也可抑制DCs刺激T细胞增殖的能力;沙丁胺醇联合丁氧胺也可抑制DCs刺激T细胞增殖的能力,但丁氧胺既无明显阻断沙丁胺醇的效应,亦无显著的协同作用。结论:β2受体激动剂沙丁胺醇通过下调DCs表面MHC-Ⅱ和共刺激分子表达,从而下调DCs功能,还能促使造血干细胞向DCs分化;β2受体阻断剂丁氧胺对DCs免疫递呈功能的影响类似于β2受体激动剂沙丁胺醇的作用;丁氧胺与沙丁胺醇共同应用未见明显阻断或叠加作用。因此,沙丁胺醇和丁氧胺可能通过β2受体以外的途径调节DCs免疫功能。

Objective： To explore the mechanisms of salbutamol regulating the immune function of rat bone marrow-derived DCs. Methods： SD rat bone-marrow cells were isolated from rat femur under the asepsis condition. The immaturation dendritic cells were induced from haemopoietie stem cells by rrGM-CSF ＋ rrIL-4 for 8 days in vitro. The maturation dendritic cells were stimulated by LPS for another 2 days. Salbutamol, butoxamine, and salbutamol ＋ butoxamine were added into the culture system of immaturation dendritic cells respectively. The morphology of DCs was displayed by fluorescence inversion microscope, and the cell surface markers on dendritic cells were detected by flow eytometer. The effect of salbutamol on DCs antigen presenting capacity was evaluated by allogeneic mixed leukoeytes reaction（MLR） between DCs and T cells. Results： There were no significant difference within DC＇s morphology in any groups. Salbutamol could up-regulate the expression of OX62, and reduced CD86, CD80 and MHC class Ⅱ on DCs surface, but there were no obvious effects on CDlle. The expression of CDlle, CD86, CD80 and MHC class Ⅱ were obviously down-regulated by butoxamine, except OX62 were down-regulated slightly. Salbutamol combined with butoxamine could down-regulate the expression CDllc, CD86, CD80 and MHC class Ⅱ on DCs, but could up-regulate the expression of OX62 on DCs. Both salbutamol-treated DCs and butoxamine-treated DCs could weaken the T cells proliferation dramatically in MLR. Salbutamol ＋ butoxamine-treated DCs could also inhibit the T cells proliferation in MLR, but there were no antagonism effects between salbutamol and butoxamine. Conclusion： Salbutamol could down-regulate the antigen presenting function of rat bone marrow-derived dendritic ceils via decreasing the expression of MHC class 11 and co-stimulatory molecules, but could promote the differentiation of RBM DCS. The effect of butoxamine on the antigen presenting function of RBM DCS was similar to salbutamol and couldn＇t reverse the effects of salbutamol, so salbutamol and butoxamine could inhibit the antigen presenting function of DCs and not via β2-adrenergic receptor pathway.